We test a taxi service that pinpoints where you are and dispatches its nearest driver. Does it work better than simply standing on the roadside in the hope of waving down a passing cab?

It's late in the evening and you're in a strange part of town. You dial a number on your mobile, and far away an unseen computer hums into life. It looks at information from your phone, analyses data from a satellite 35,000km above your head, and a few seconds later a black cab pulls up.

Science fiction? Far from it. This is the technology behind a new taxi service called Zingo operating in London.

It works by pinpointing a potential passenger's location, and matching them with the service's nearest taxi. To find the passenger, it uses location based services (LBS) technology - a system which allows mobile phone operators to tell where an individual user is by looking at which mobile phone mast the phone is locked on to. The taxis are equipped with global positioning system (GPS) receivers which can tell the vehicle's position using signals from satellites, and this information is sent continuously to the control centre.

"Where to, mate?"

When a potential passenger rings up, the service receives information about the caller's position from the mobile phone company, finds the nearest cab from the GPS data, and then automatically routes the call through to the cab driver. It is then a simple matter of talking to the cabbie and giving the precise address - the cabbie can also estimate how long it'll take to get there.

If the taxi doesn't turn up, the caller can be reconnected to the cabbie to find out what's holding him up - much more reassuring than calling a radio dispatcher who will inevitably - it often seems - give the standard answer that the cab will arrive in five minutes.

Road test

But does a hi-tech LBS and satellite-based hailing system work better than the time-honoured method of standing at the curb, waving frantically and yelling "taxi"?

No more waiting on the pavement

The application of a little technology can certainly make taxi-hailing a warmer, dryer and far more comfortable affair, says Zingo's marketing manager Mark Fawcett. "You can hail a cab from inside, while you're finishing your meeting or your drink or whatever."

So much for the theory. Armed with a mobile phone, I put the service through its paces.

Test one: Edgware Road, central London, Wednesday evening rush hourMy call is connected in 20 seconds to a driver, who says he'll arrive in about eight minutes. Not exactly instant, but better than nothing. The trouble is that almost as soon as the conversation with the cabbie is over, not one but three empty black cabs drive past with For Hire signs lit. It's moral dilemma time: should one wait for the Zingo cab, or hop in one of the passing ones and cancel the booked taxi? I decide on the former, and sure enough, eight minutes later, my cab arrives.

Test two: North London, Sunday morningMy call is greeted with a message that the service is currently not working - please try later.

Test three: Shepherd's Bush, west London, Tuesday eveningThis time the service is working, but after a pause I am informed that there's no Zingo taxi in the area.

So far it seems as though the traditional method of waving and yelling is more effective than relying on cell phones and satellites, but Zingo is still in its infancy with only 400 cabs on the road.

More cabs are being signed up each week, Mr Fawcett says, with a target of several thousand in the near future. And although the service only works automatically with mobile phones on the O2 and Vodafone networks at present, he expects other networks to join up in the next few months. In the meantime, users of other networks are connected to a call centre where they have to give their address before they can be passed on to a driver.

For now I'll be hailing my own cabs, but next time it's cold and wet outside, I'll be tempted to stay warm and let my phone do the hailing.

Send your comments on this story:

It's no fun looking for a cab at night, and if you're a woman on your own you feel particularly vulnerable. Knowing that it's possible to book a black cab from indoors, rather than look for one on the streets, is great.Beckie Crum, UK

I've been a Zingo user for the past three months and I think it's great; I use it all the time in London. I've got connected to a cab every time and it's never been more that three minutes before the cab arrives. However, empty cabs do go by sometimes! One problem is that it can be hard to identify the arriving Zingo cab in the street: this needs to be fixed. But there's the security of knowing someone is seeking you, and it's cheaper than some rival companies.Roger Gould,
UK

I notice that the network operators release the mobile user's location. What are the privacy issues here? I see in Zingo's privacy statement that "by calling the Zingo hailing number you give your consent to the use of your information as described above" and their treatment of the data seems fair. But can Orange/Vodaphone etc release or sell information about where I am to anyone?David Mountain, UK

Given that you're hailing a taxi and therefore won't be at that location for very long, it's not much use on its own (and anyway even if you're just phoning for a minicab you need to tell them where you are). Where it could be disturbing is if the details of your call locations were aggregated, if the network operator stored the information about where you were over a period of time and built up a profile about you. The Data Protection Act would not allow that unless you had specifically signed up to it.Neil, UK

I think the idea is very good. In fact the principle could also be installed in our age-old bus service, with some sort of real time indication when the next bus will arrive. This will mean an end to wasting 30 minutes waiting for a bus that should be every 6 minutes.Chris Mountford, UK

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